New YorkK AGRICULTURAL EXPERIMENT STATION, - 149 
that there was an actual increase in yield of 14.5 per ct. from 
spraying. 
THE PARASITIC DARLUCA, 
In 1898 Dr. Halsted” found a fungus known as Darluca filum 
Cast., which is a parasite upon many rusts, attacking asparagus 
rust. 
This parasitic fungus has been so prevalent during the past two 
years that most growers of asparagus are familiar with it. Its 
abundance and the rapidity with which it spreads upon the uredo 
or summer stage of the rust has led others besides growers to 
anticipate remarkable benefits from its attacks on the rust. 
During the past summer (1900) Darluca attacked the ecidial 
stage of the rust about June 10. Ten days later all the rusted 
asparagus stalks were covered with the Darluca. Notwithstand- 
ing the above condition, there was a severe outbreak of the sum- 
mer stage of the rust on seedling beds about July 1, which was 
immediately followed by the Darluca. About the middle of 
August as severe an outbreak of the summer stage of the rust 
as has ever occurred in previous years appeared on the cutting 
beds. This in turn was followed by the Darluca. The same con- 
ditions were repeated again in September on the late watery 
shoots of asparagus. All of these attacks of the Darluca were 
followed by the formation of an abundance of the teleuto spores 
or winter stage of the rust. 
Cross sections of the sori or rifts of the summer stage of the 
rust frequently show the condition illustrated in Fig. 2, Plate XI, 
that is, the sori will be filled with the uredo or summer spores 
while beneath them a layer of the winter spores will be forming. 
We have even found sori in which the uredospores were appar- 
ently destroyed by Darluca while at the bottom of the sorus a 
layer of evidently healthy winter spores would be found. 
The formation of the winter spores of the rust on the same 
plant where the uredo stage had been attacked by Darluca, com- 
bined with the conditions shown in Fig. 2, Plate XI, all indicate 
that the Darluca attacks the spores of only the ecidial and uredo 
aN, J. Agr. Exp. Stas. Bul. 129, p. 15. 
